Hydraulic brake



Jan. 3, 1939. G. A.BURROW,

HYDRAULIC BRAKE 5 Sheets-Sheet l Filed Aug. 24, 1936 eorgeL/lfow l N V E N TO R ATTORNEY G. A. BURROW .HYDRAULIC BRAKE Jan. 3, 1939.

Filed Aug. 24, 1936 3 Sheets-Sheet 2 f orgeulfoW' v INVENTQR l 'B *I Q :ATTO'RNEY G A. BU RROW HYDRAULC BRAKE Jan. 3, 1939.

5 Sheets-Sheet 5 Filed Aug. 24, 1956 Patented 3, 1939' UNITED STA-TES PATENT OFFICE The invention relates tohydraulic or fluid brakes particularly adaptedvfor use ,in connection with yvehicles but applicable to various uses, and has for its object to provide abrake where- A in the brake shoes are forced outwardly against spring action by an expansive annular member, which brings the brake shoes into engagement with the inner periphery of the brake drum for braking the rotation of the drum.-

A further object is to provide means whereby the brake shoes. will be caused to uniformly engage the brake drum periphery during the braking operation thereby insuring -f uniform wearing'oi the shoes throughout their length.

A further object is to provide an adjustable link connection between the front ends of the shoes and a stationary .housing whereby the front ends ofthe vshoes will be caused to engage the brake drum periphery and grip the same with an increasing pressure along with theincreasing pressure of the shoes when `forced outwardly.v

Also to provide adjusting means whereby the front ends of the shoes may be adjusted for varied engagements.

A further object is to provide limiting means for the shoes for preventing engagement of the body of the shoe with the brake drum when the lining of the shoe is worn toa predetermined degree, 4thereby preventing scoring of the brakeY drum.

A further object is to provide an expansion spring within vthe annular expansion member for normally maintaining the same attened under the iniluence of the pressure exerted on the yshoes by their springs.

A further object" is to provide insulating means .between the shoes and the annular expansible brakes and adjusting means whereby the timel of operation of the brakes may be varied according to the wear on the various brakes.`

A further object is to form the bellows cylin-V ders around telescopically engaged tubular members, the inner one of which is provided with a plurality of apertures, said tubular members positively guiding the parts and the apertures allowing a tapering oi o! pressure at the ends of the brake pedal movement.

A further object is to provide a disc clutch type of brake wherein the annular expansible member is disposed between discs for expanding the same to a braking position.

With the above and other objects in View the invention resides in the combination and ar- .rangement of parts as hereinafter set forth,

shown in the drawings, described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of what is claimed Without departing from the spirit of the invention.

In the drawings:

Figure l is a vertical longitudinal sectional view through the upper half of the brake.

Figure 2 is a vertical longitudinal sectional view through the brake, taken on line 2 2 of Figure 3.

Figure 3 a vertical transverse sectional view through the brake' taken on line 3- 3 of Fig- Figure 6 is a detail sectional view taken on line 6 6 of Figure 3.

Figure -7 is'a detail front view of a portion of the brake, showing the adjustable link -connection between one of the brake shoe ends and stationary housing.

Figure 8 is a view-similar to Figure 7, but showing in dotted lines the brake shoenmovement, and link connection.

the

Figure 9 is a perspective View of the link connection.

Figure 10 is a. vertical longitudinal sectional view through 'one side of a disc type of brake showing the annular expansible member between the discs.

Figure 11 is a longitudinal sectional view through one of the bellows actuating members;

,Figure 12is a rear view of the pedal carried member for compressing the bellows.

. Figure 13 is aview in elevation of a conventional form of vehicle brake pedal, showing the brake actuating bellows in connection therewith. Referring to the drawings, the numeral I designates the brake drum, which may mount a wheel in any way desired. The brake drum l is of the internal type and has a braking surface 2, against which the brake shoe linings 3 engage during a braking operation. In the present brake, a plurality of shoes 4 are used, and preferably four as shown. 'I'he linings 3 of the shoes are secured thereto in any suitable manner, however conventional rivets 5 are shown for purposes of shaped as shown in Figure 1, and have spaced anges 6 and 1, which are in the path of spaced limiting lugs 8 and 9 carried by the stationary brake housing I0, which may be supported on the vehicle in any suitable manner, for instance on the rear, axle housing II, as shown in Figure 1, or on the axle spindle I2, as shown i'n Figure 2. The brake shoes 4 are limited in their outward and inward movement by the lugs 8 and 9, however the lugs 9 are positioned whereby they do not stop the outward movement of the shoes until there has been an excessive wear on the brake shoe linings 3, but at no time do they allow the brake shoe body to engage the braking surface 2 of the brake drum. It will be noted that the spaced'lugs 8 and 9 overlap the adjacent ends of the brake shoes, hence the brake shoe ends are stopped and limited at the same time, and are maintained, when in their inner positions, under the influence of the expansion springs I3 in concentric relation and the same lugs take care of adjacent shoes.

flexible pipe 23, which 'I'he expansion springs I3, which normally maintain the shoes 4 in their inner position, are disposed in openings I4 in the shoe flanges and are interposed between lugs I5 carried by the shoes and arms extending inwardly from the stationary housing-III. Disposed within a channel I1, formed in the channel housing I0 and by a removable ring I8, is a pliable annular member |13,- preferably formed of a rubberized fabric, and which annular member isadapted to be radially extended by the forcing of fluid therein forv simultaneously forcing.A the brake shoes 4 outwardly for a braking operation. Disposed within the annular expansible `member I9 is an expansion spring 20, which normally maintains the ring I9 longitudinally extended, as clearly shown in Figure 5, and at which time the shoes are in their inner positions. The end convolutions of the expansion ring are disposed in annular channels 2|, which prevent wear on the expansible member I9. Fluid, under pressure, is supplied to the pliable expansible member I9 through an angular pipe 22, extending through the stationary housing I0 and connected to a leads to fluid supply means. The two upper shoes are provided with a bleeder pipe between their ends, and which bleeder pipe extends radially inwardly and is connected at tothe pliable expansible member I9 and forms means, when the caps 26 are removed, for allowing the escape of air during the fluid iilling of the system. The bleeder pipes 24 are disposed within recesses 21 in the adjacent ends of the ilanges and access may be had thereto through the housing I0 by removing the closures 28. Fluid enters the pliable expansible member I9 through pipe 22 and then expands the member I9, which action will cause a radial outward movement of all the shoes simultaneously until the brake shoe linings engage the `brake surface 2 of the drum for the braking operation.

Ordinarily hydraulic brakes are constructed Awith two brake shoes, pivoted at one of their ends, and controlled by oil cylinders. When pressure is applied to such a structure, the free ends of the shoes are forced against the drum illustration. The brake shoes are I- links 32, said links being four movable shoes, which are so' suspended that they are all energized alike and means is provided to adjust the braking effect of the shoes as desired. The adjusting means comprises rotat- Iably adjusted blocks 29 for each shoe and rotatably mounted in bearings of the stationary housing I0. The blocks 29 have pivotally mounted eccentrically therein at 30, the arms 3I of the provided with arms 33, pivotally mounted in bearings 34 in the front ends of the shoes as clearly shown in Figures 'I and 8. The blocks 29 are provided with threaded recesses 35 in their peripheries, any of which are adapted to be placed in registration with threaded recesses 36 in the bearing 31 for the block, and to receive a holding screw 38 for holding the block in adjusted position after the link connection 32 has been properly adjusted for insuring a uniform clutching or braking engagement with the brake drum surface 2. Three of these adjustablepositions are shown in Figure 7. It will be seen by referring to Figure 4 that when the shoes come into contact with the drum surface 2 and the drum is revolving, the tendency will be to assume the position shown in dotted lines in Figure 8, and that the links 32 would tend to straighten out and align themselves with the circumference of the drum.

The crank movement is limited to the point where the shoes come into full contact with the drum, and the energizing effect takes place in the following manner. The shoes, upon contact with the drum, are urged to revolve with it and the crank action tends to straighten out, and in doing so helps to push the shoes tight against the drum.

From the above it will be seen that a brake is provided wherein the shoes will uniformly engage the brake drum, and the link connections will tend to further energize the shoes.

Referring to Figure 10 wherein a modified form of brake is shown, in this form the brake drum I has disposed therein, in spaced relation, discs 40 and 4I, which discs are normally forced towards each other by means of a contractible spring 42. Discs 40 and 4I are splined at 43 on the stationary housing 44 and are normally out of braking engagement with the drum surfaces 45 and 46. The outer faces of the discs 40 and 4I are provided with linings 41 which cooperate with the drum surfaces 45 and 46 when the discs are forced apart. Secured to the inner adjacent sides of the discs 40 and 4I are insulation discs 48, which act to prevent transmission of the heat incident to the braking operation to the pliable expansible member 49, interposed between the discs, and which expansible member is normally maintained in a ilat condition as shown ir Figure 10 by a coiled expansion spring 50. Fluid is supplied to the member 49 through a fluid supply pipe 5I and the expansible member 49 is provided with a bleeder pipe 52 for allowing exhaust of air during the lling of the system. In operation, when fluid is forced into the pliable expansible member 49, the discs 48 and 4I are forced outwardly until their linings have a braking engagement with the Abrake drum surfaces 45 and 46. Upon release of pressure the contractible spring 42 forces-the discs together for an unbraking operation.

Referring to Figures 11 to 13 inclusive. In Figure 13 -is shown at 53 a conventional form of' brake pedal, to which is connected a rod 54, which extends rearwardly through astationary plate. 5,5 carried by a vehicle, and terminates in a plurality of arms 56, which are in line with the adjustable cylinder heads 5l.v The 'adjustable cylinder heads are ladapted to be extended to vary the timing of operation of any particularv brake, thereby allowing all brakes to be synchronized. It will be noted by referring to Figure 13, that one of the cylinders will have a delayed operation. The cylinder heads 51 are threaded into bosses 58 carried by plates 59, to which is anchored the bellows cylinders 60. The bellows cylinders are maintained in form by internal and external rings- 6I, therefore collapsing inwardly or outwardly of the walls of the bellows is prevented. Connected td the other ends of the bellows are plates 62 having tubular extensions 63 which terminate in pipes 64, which lead to the brake pipes 22 and 5I. Interposed between the plates 59 and 62, within the bellows, is an expansion spring 65, which normally maintains the bellows extended. The plate 59 of the bellows is provided with a tubular extension 66, which is slidably mounted in the tubular extension 63, therefore it will be seen that the bellows will be axially collapsed extended and positively guided during its movement. The tubular extension 66 is provided with a plurality of apertures 61, through which fluid passes during the collapsing and extending of the bellows.A It will be seen, however, that as the brake approaches its 'extreme braking operation some of the apertures 61 will be within the tubular member G3, hence there will be a gradual applicationof the brake incident to lreduced aperture area through which fluid mayvpass. A check valve 58 is provided in the upper end of the tubular member 68, and which normally closes a passage through which fluid may be forced inilling the system.

The invention having been set forth what is claimed as new and useful is: u

1. A brake comprising a drum having a chamber therein, a stationary housing extending into the chamber of the drum, a tubular expansible member carried by the portion of the housing within the chamber of the drum, .arcuate brakev shoes within the chamber of the drum and engaged by the tubular expansible member and forced outwardly into braking engagement therewith, link connections betwee'n Ith'efsl'ioes and the housing for insuring uniform. gripping of the shoes throughout their length and means for varying the angle of movement of the links for adjusting the self energizing force of the shoes and means,\fornormally forcing said brake shoes inwardly.

/2.` A brake comprising a rotatable drum, radially movable concentrically arranged shoes within the drum, spring means for normally forcing said shoes inwardly, an expansible, pliable annular member within the drum and' adapted to force the shoes outwardly for a braking operation, a housing for'said drum and a link connection between the housing and the front ends of the shoes, and forming means for causing a positive v braking operation of the shoes throughout their length said link connections comprising arms pivotally connected inl o'ff center relation in r'otatablyl adjusted l. members carried by the stationary housing.

3. A brake comprising a rotatable drumra dially movable concntrically arranged shoes Within the drum, spring means for i normally forcing said shoes inwardly, an expansible, pliable annular member within the drum and adapted to force the shoes outwardly for a braking operation, a housing for said drum and a link connection between the housing and the front endof the shoes and forming means for causing a positive brakingoperation of the shoes throughout their length, rotatable adjustable members carried by the housing, said links being pivotally connected to the rotatably adjustable members in off-center position. f

GEORGE A. BURRow. 

